Lipid rafts are membrane microdomains that are enriched in cholesterol and glycosphingolipids. They were originally implicated in lipid trafficking, but now appear to be involved in a plethora of biological processes including signal transduction, endocytosis and protein and lipid sorting. Studies of lipid rafts have been hampered by the lack of appropriate methods to analyze them in intact cells and an insufficient understanding of their mechanism of formation and biological function within cells. This conference will examine several important issues related to the structure and function of lipid rafts including: i) biophysical and biochemical methods for the visualization and analysis of lipid rafts; ii) biogenesis of rafts and their size; iii) the role of rafts in signal transduction.; and, iv) the role of rafts in endocytosis and protein processing. [unreadable] [unreadable]